Abstract: A dimensionally stable gas diffusion electrode and a method for the fabrication thereof are described. The electrode comprises at least an electroconductive catalyst support material to accommodate a catalyst material-containing coating composition and an electrical connection, the catalyst support material (4; 11) being a fabric, bonded fibre web, foam, sintered metal body or felt of electroconductive material, an expanded-metal plate or a metal plate provided with a multiplicity of perforations (2, 8), on top of which plate the catalyst material-containing coating composition (5) is applied, the material, if its inherent stiffness is inadequate, being permanently joined mechanically and electroconductively to a gas-permeable, alkali-resistant metallic baseplate (1; 7), especially comprising nickel or its alloys.

Abstract: Electrode at least comprising an electroconductive support of a titanium-palladium alloy, titanium, tantalum or compounds or alloys of titanium or of tantalum, an electrochemically active coating and an interlayer between the support and the electrochemically active coating, wherein the interlayer consists of titanium carbide and/or titanium boride and is applied to the support by flame or plasma spraying. Process for producing these electrodes and their use in an electrochemical cell for producing chlorine or chromic acid.

Abstract: The invention describes a process for the electrolysis of an aqueous solution of alkali metal chloride, in particular sodium chloride, by the membrane process with an aqueous solution of alkali metal hydroxide, in particular sodium hydroxide, as catholyte, where the temperature of the alkali metal chloride solution in the anode half-element and/or the volume flow rate of the alkali metal chloride solution in the anode half-element are set in such a way that the difference between the temperature of the alkali metal hydroxide solution at the entry into the cathode half-element and the temperature of the alkali metal hydroxide solution at the exit from the cathode half-element are not greater than 15° C.

Abstract: The invention relates to an electrolysis cell comprising an anode frame (26), an anode (24), a cation-exchange membrane (34), a gas diffusion electrode (32), a current collector (10) and a cathode frame (12), with the anode (24), the cation-exchange membrane (34), the gas diffusion electrode (32) and the current collector (10) being held together elastically so that there is no gap between the individual components anode (24), cation-exchange membrane (34), gas diffusion electrode (32) and current collector (10). The elastic cohesion is preferably achieved by the current collector (10) being elastically fastened to the cathode frame (12) and/or the anode (24) being elastically fastened to the anode frame (26).

Abstract: The invention relates to a process for the electrochemical preparation of chlorine from aqueous solutions of hydrogen chloride in an electrolysis cell, comprising an anode chamber and a cathode chamber, the anode chamber being separated from the cathode chamber by a cation exchange membrane, the anode chamber containing an anode and the cathode chamber a gas diffusion cathode, and the aqueous solution of hydrogen chloride being passed into the anode chamber and an oxygen-containing gas into the cathode chamber, and the oxygen pressure in the cathode chamber being at least about 1.05 bar.

Abstract: A process for electrolyzing an aqueous solution of hydrochloric acid to chlorine in an electrochemical cell provided with an anode compartment and a cathode compartment including at least one gas diffusion cathode comprising an electrically conductive web provided on at least one side thereof with a coating of a catalyst for the electroreduction of oxygen comprising rhodium sulfide and optionally containing at least one fluorinated binder incorporated therein, comprising introducing aqueous hydrochloric acid containing contaminant species into the anode compartment and oxygen into the cathode compartment while impressing a direct electric current on the cell.

Abstract: This invention relates to an electrochemical half cell having a gas diffusion electrode as an anode or cathode, in which the gas space behind the gas diffusion electrode is optionally partitioned, for pressure equalization, into gas compartments which are joined to the gas diffusion electrode and which can be removed from the half cell or changed as a unit.

Abstract: The invention relates to a process for the electrolysis of sodium chloride-containing brine with parallel operation of amalgam electrolysis units (5) and membrane electrolysis units (4) with a common brine circuit using a mercury-resistant oxygen consumable cathode in the membrane electrolysis unit (4).

Abstract: The invention relates to an electrochemical half cell (1) comprising at least one electrode space (3, 15) for receiving an electrolyte (100), a gas space (2), and at least one gas diffusion electrode (14) as anode or cathode separating the gas space (2) and electrode space (3, 15), in which the gas space (2) is subdivided into two or more superimposed gas pockets (2a, 2b), in which gas inflow and gas outflow takes place through separate openings (7) and (12a, 12b, 12c, 12d) and the pressure on the electrolyte side of the electrode (14) is compensated by an opening in the respective gas pocket (2a, 2b) for the electrolyte.

Abstract: The invention relates to an electrochemical half-cell (1) with a gas diffusion electrode (7) as cathode or anode wherein the gas chamber (6) is divided in particular into two or more gas pockets (6a, 6b, 6c) arranged one above another, the electrode chamber (2) of the half-cell (1) being divided into compartments (2a, 2b, 2c) which for the passage of the electrolyte (23), are connected to one another in cascade fashion via chutes (17), (18), (19).

Abstract: The invention relates to an electrochemical half-cell consisting in at least one electrode chamber 14 for accommodation an electrolyte, a gas chamber 23 and at least one gas-diffusion electrode 5 as anode or cathode separating gas chamber 23 and electrode chamber 14, in which the gas chamber 23 is divided into two or more gas pockets 20, 20' superimposed on one another after the manner of a cascade, with which the gas supply or gas discharge takes place through openings 11, 12 to the electrolyte 22.